I recently had the ring where the key ring attaches break on my door opening and locking key fob and had to switch to the other one that came with the car in 2005. Its never been used and has worked before.

However, it does not seem to work? It worked once yesterday and then stopped. Any ideas? Do I need to change the battery? It seems since the old one that was used daily battery worked fine the second one should have a battery that is even better?  

Hate to have to go to the dealer.

Thanks for looking.

Yep, just pop them open and swap in fresh batteries.  Even if the spare wasn't being used, it's still possible for the batteries to die over time.  They probably take CR2032 batteries (which is what my 02 4Runner remote takes), which are available just about anywhere.  

-Parke1

Had a similar problem with my wifes vehicle....I bought a used fob and just replaced the guts from hers into the used fob.

Great, thanks. Just went and bought a new battery. Problems solved. Its a CR2016.